İstanbulspor Kulübü is a Turkish football and sports club founded by Istanbul High School students in 1926. In 2004–05 they were relegated from the Turkish Süper Lig (Super League) to TFF First League. For many decades it was the fourth most famous and well-developed professional football club from Istanbul, coming after Beşiktaş, Galatasaray, and Fenerbahçe.